One type of pump for injecting large volumes of liquid into a well is a centrifugal pump. The pump has a large number of stages of impellers and diffusers. The pump is mounted horizontally on the surface and has an intake chamber connected to one end. A shaft extends through the intake chamber to an electrical motor for driving the pump. Rearward thrust is created due to the action of the pump. This thrust is absorbed by a thrust bearing assembly mounted between the intake and the electrical motor.
The prior art thrust bearing assembly has a thrust runner and stationary bearing located within a housing. The bearings are located within a chamber that is filled with a clean lubricating oil. A seal seals around the shaft at the point where it passes from the intake chamber into the lubricant chamber. It is important to avoid contamination of the oil by the water being pumped. While these types of pumps work very well, the seal between the intake chamber and the thrust bearing housing must be replaced from time to time due to wear. This can be a difficult task because it requires removing the entire thrust bearing assembly from the pump. During the removal time, the pump will be down and cannot be operated.